There is an established need to climb various upright structures, for maintenance or for performing various jobs not easily performed from the ground. Ship s masts at times require a person to climb the mast to unfurl sails, paint the mast, replace a pulley, etc. Other upright structures, such as trees require periodic maintenance, such as cutting out dead limbs, removing selected branches from around electric wires, etc. Telephone poles require periodic maintenance, requiring a repairman to climb the pole. Some building structures, such as steel frame high rise buildings require workers to perform work while suspended from a vertical column. Often the worker is at risk of injury from a fall, where no safe means for climbing the upright structure is provided. The man lift apparatus disclosed herein, provides a safe, adjustable means to support the user while climbing or working on an upright structure.
1. Field of the Invention
This invention relates to a man lift apparatus for climbing masts onboard ships, as well as climbing other vertical structures, such as trees, telephone poles, man-made construction frameworks, and other upright pole-type supports.
2. Background of the Invention
U.S. Pat. No. 4,595,076 issuing to Benjamin Gober, on Jun. 17, 1986 discloses a tree climbing apparatus having a metal strap attached on one side to a rectangular plate, and adjustably secured to the other side of the rectangular plate after encircling the strap around the tree.
U.S. Pat. No. 286,644 issuing to J. Seagrave and E. Fuller on Oct. 16, 1883 discloses a fire escape connected to an endless rope support from above by a pulley.
U.S. Pat. No. 4,407,391 issuing to Greenway et al on Oct. 4, 1983, discloses a safety device for pole climbers. A two hinged annular yoke portions are releasably secured about a pole, and pivoted blades mounted to the underside of the yoke are biased between a pole engaging position and a manually retractable position.
U.S. Pat. No. 4,520,895 issuing to James Armstrong on Jun. 4, 1985 discloses a building wall descent device having a manually operated brake means.
U.S. Pat. No. 5,351,783 issuing to Alfredo Celli on Oct. 4, 1994 discloses a self propelled vehicle for climbing pole-shaped elements, having a pair of counteracting wheels rotatable about a horizontal axis.
U.S. Pat. No. 3,968,858 issuing to Douglas Vollan et al. on Jul. 13, 1976 discloses a sailboat mast climbing device, utilizing a vertical track secured to the mast, and hand and feet climbing devices which are slidably received in the track. Each climbing device includes a brake for locking the climbing device to the mast.
U.S. Pat. No. 2,842,300 issuing to J. Johnson on Jul. 8, 1953 discloses a hand operated pole climbing aid, having a U-shaped central connecting portion with teeth, and lever arms vertically offset and raise the central connecting portion from the ends of the lever arms. A chain is secured between the lever arms to grip the pole when weight is applied to hand grips located at the ends of the lever arms.
The man lift apparatus comprises a handle secured to first and second arms which extend partially around an upright pole-type support for supporting a user at a selected position upon the upright support, when the handle is lowered to a substantially horizontal position.. When the handle is raised substantially parallel to upright pole-type support, the man lift apparatus may be removed, adjusted, raised or lowered upon the upright support. The user slides the lift apparatus upon the upright support, with the handle positioned substantially parallel with the upright structure. Once positioned about the upright support, the user lowers the handle to a position which places a camming plate against the front side of the upright pole-type support, with the second arm extending in an upward incline from the handle, which extends across a portion of the front side, the second side and the back side of the upright pole-type support. The first arm extends substantially horizontally in a first direction from the handle to at least partially engage a portion of the front side and the first side of the upright pole-type support. The second arm extends in a second, opposite, inclined direction from the handle to engage the second side, back, and a portion of the first side of the vertical support. The distal ends of the first and second arms are substantially parallel to each other, and spaced a distance greater than the cross-sectional thickness of the upright pole-type support. When the user places at least a portion of their weight upon the handle, the man lift apparatus engages the upright pole-type support to provide a stable means to support the user at a selected location on the upright support. Rope, cord, cable, chain or straps are preferably removably secured to the man lift apparatus, to support a bosin""s chair, seat harness, body harness, or support belt, which is secured about the user, for safety.